Family Merit and Individual Merit as Bases for Selection. Part II

Lush, Jay L.

doi:10.1086/281532

Cited by 49 publications

(56 citation statements)

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“…Plant and animal breeders have long been interested in the problem of progress under selection for different mating systems (e.g., Lush 1947;Madalena and Hill 1972;Goodwill 1974;Katz and Enfield 1977). This is relevant to our study because inbreeding, bottlenecks and mating systems all can be used to address the relationship between the loss of heterozygosity and changes in genetic variance.…”

Section: Discussionmentioning

confidence: 99%

INBREEDING: ITS EFFECT ON RESPONSE TO SELECTION FOR PUPAL WEIGHT AND THE HERITABLE VARIANCE IN FITNESS IN THE FLOUR BEETLE,TRIBOLIUM CASTANEUM

1996

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Abstract.-We report our studies of the effect of inbreeding on the response to selection for increased pupal weight in the flour beetle, Tribolium castaneum. We also report the effects of inbreeding and selection for pupal weight on the heritable variation in fitness and fitness components. We created replicate and independent inbred lines with Fvalues of 0.00, 0.375, and 0.672, by 0, 2, and 5 generations, respectively, of brother-sister mating of adult beetles from an outbred stock population. Subsequently, we imposed artificial within-family selection for increased pupal weight in each of 15 inbred lines for eight generations; each line had its own paired, un selected control. We compared the response to selection across the three levels of inbreeding with theoretical expectation, and investigated the effects of inbreeding and selection on fitness variation among families within all 30 selected and control lines. Among-line variation in pupal weight increased with increased inbreeding prior to selection but diminished with directional selection. Inbreeding reduced the realized heritability of pupal weight concordant with quantitative predictions of additive theory. Mean fitness, measured in several ways, declined with inbreeding and declined further with selection. In contrast, the genetic variation for fitness in the inbred and selected lines lines equalled or exceeded that of the outbred controls. Our results suggest that inbreeding and selection may affect traits in different ways depending on the relative amounts of additive and nonadditive genetic variation.

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Section: Discussionmentioning

confidence: 99%

INBREEDING: ITS EFFECT ON RESPONSE TO SELECTION FOR PUPAL WEIGHT AND THE HERITABLE VARIANCE IN FITNESS IN THE FLOUR BEETLE,TRIBOLIUM CASTANEUM

1996

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“…Robertson (1961) showed an approximate result for the case where individual records (F) and means of full-sib families (F) are used in the index I (P -F ) + w( F -P), where P is the mean of the population and w is the weight given to family information. For large family size, the optimum value of w (that which maximizes the correlation between breeding values and index values of individuals) is approximately w = (1 -PF5)/PFs for full-sib families (Lush, 1947). The variance between family means is scaled by w2 and, hence, the intraclass correlation of full sibs for index values is 1 -PF• Thus, a first order approximation of the effective size under index selection can be obtained from eqn (36), where C2 = i( 1 -oFS).…”

Section: Index Selection In Animal Breeding Practicementioning

confidence: 99%

Developments in the prediction of effective population size

1994

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Effective population size is a key parameter in evolutionary and quantitative genetics because it measures the rate of genetic drift and inbreeding. Predictive equations of effective size under a range of circumstances and some of their implications are reviewed in this paper. Derivations are made for the simplest cases, and the inter-relations between different formulae and methods are discussed.

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“…Lush (1947) has an excellent discussion of interpreting biometrical relationships to combine information from various relatives in an index to make genetic gain from selection on the index. Skjervold and Odegard (1959) and Young (1961) = mean milk production of the cow expressed as 303-2X-ME lactation yield minus a regressed herdmate average which is defined later.…”

Section: Introductionmentioning

confidence: 99%